Homogenate extraction of total phenols from Nelumbo nucifera rhizome and evaluation of antioxidant activities

This study applied the homogenate extraction method to extract total phenols (TP) from Nelumbo nucifera rhizome, and evaluated the antioxidant activities of TP. After the single-factor experiments and optimization using response surface methodology, the optimized homogenate extraction parameters for obtaining TP from Nelumbo nucifera rhizome were as follows: ethanol concentration, 37%; liquid-material ratio, 15 mL/g; extraction time, 27 s. With these conditions, the TP yield was 0.36 +/- 0.04%. When the concentration was 30 mg/mL, the 2,2-diphenyl-1-(2,4,6-trinitrophenyl)-hydrazyl and hydroxyl radical scavenging rates of TP were 80.15 +/- 5.12% and 67.88 +/- 6.34%, respectively. Compared with the traditional extraction, the homogenate extraction has the higher TP yield and shorter extraction time. In addition, the TP obtained by homogenate extraction have the higher antioxidant activities than traditional extraction. To sum up, the homogenate extraction is an efficient and rapid method for extracting TP from Nelumbo nucifera rhizome.